Method of cracking and processing petroleum



Oct. 4, 1932. 1. c. BLACK 1,880,717

METHOD OF CRACKNG AND PROCESSING PETROLEUM Original Filed May 17, 1924 Patented ct. 4, 1932 UNITED STATES PATENT OFFICE JOHN C. BLACK, OF BEVERLY HILLS, CALIFORNIA, ASSIGNOR TO GASOLINE PRODUCTS COMPANY, INC., OF WILMINGTON, DELAWARE, A CORPORATION 0F DELAWARE METHOD 0F CRACKING AND PROCESSING PETROLEUM.'

Original application :Bled May 17, 1924, Serial No.V 714,070, now Patent No. 1,782,676. Divided and this application led March 4,

This application is a division of a prior co-v pending application Serial No. 714,070, filed May 17, 1924, which has matured into Patent No. 1,782,676, which prior application is a continuation in part of application for Letters Patent Serial N o. 602,439, filed Nov. 21, 1922.

In my application N o. 602,439 I describe a method of introducing fresh supply oil into the cracking or converting system by having a separate heater for the preliminary heating of the fresh oil or make-up oil and introducing it into the carbon precipitating chamber or direct into an expansion drum from whence it goes to the fractionating tower. By my new method, I do not use a separate heater setting but use a heating coil `which I have denominated an economizer coil and which I set in the terminal combustion space of the main furnace, the coil in that position absorbing sufficient tory results. Furthermore, by my new 'arrangement of apparatus, I am enabled to pass cycle stock through the economizer coil: this stock is the same as that passing through the main cracking coils and may be drawn from the same source of suppl I am also able to introduce new make-up oil through the economizer coil and discharge it either into the mixing chamber under pressure or into the header connecting with the fractionating tower, as described in my application Serial No. 602,439.

In the apparatus disclosed in this application the main heating and cracking coils, to gether with the carbon precipitating chamber or digester and the means for operating under pressure are the same as described in m Patents Nos. 1,426,813 and 1,456,419, so that if I am' introducing the economizer oil into the carbon precipitating chamber or digester, as the case may be, it will be under such pressure as to overcome the pressure prevailing in the mixing chamber which is such as to materially prevent vaporization of the cracked oils therein, that is substantially in a liquid A phase, whereas if I discharge the economizer oil into the header or fractionating tower direct, I will not be compelled to carry such a high pressure, for the reason that the temperaheat to obtain satisfacy operating rather than to 1930. Serial No. 433,120.

ture of the oil in the economizer coil is lower than that in the main cracking coil, and, therefore, its vapor pressure is less, but I carry suiicient pressure on the economizer coil at all times to prevent material vaporization irrespective of the manner of discharge.

My preferred method of operating is to so regulate the quantity of oil passing through the economizer coil as to bring its temperature to a degree of heat approximating its incipient cracking point or preferably to a point below its carbonizing point, in order to prevent fouling of the tubesof the economizer coil. The desired temperature f will usually be between six and seven hundred degrees Fahrenheit for most oils, but it can be operated at a higher temperature if desired or even lower one, but I prefer to operate at a temperature of six hundred to seven hundred degrees Fahrenheit.

When this temperature is attained, the oil is injected into the mixing chamber, wherein it intermingles with the highly heated oil coming from the main heating or cracking coils, whereby its temperature is suddenly increased to an exceedingly active cracking temperature, the pressure being maintained in the mixing chamber sufficient to prevent material vaporization therein, from whence the mixture of oils passes to the heat exchanger, if one is employed, and then to the pressure reducing and discharge valve. The oil pumped through the economizer coil is either fresh make-up oil or cycle stock obtained from `the supply coincidentally pumped through the main heating or cracking coils. This is my preferred method of discharge the eco- -nomizer oil direct to the fractionating tower,

although this may be found desirable at times and the apparatus is so constructed as to permit of operating in that manner.

The exceptional results obtained b the introduction of economizer oil into the ighly heated cracked oil chamber is due, I believe, to the exceedingly rapid heating effect obtained thereby, whlch is practically instantaneous in its rapidity,

and is of such` degree as t'o constitute an explosive shock to the molecules of the hydropresent in the mixing carbons, especially in view of the fact that the pressure maintained on the hydrocarbons is suiiicient to prevent any material vaporization with its resultant cooling effect, thereby holding the oils in a liquid contact at the active cracking temperature due to their mixture; as for instance, if the economizer loil enters the mixing chamber at 7 00 F. and the ingoing primarily cracked oil is 900 F., and the ratio of economizer oil to the primary oil is as one is to two, then the resultant temperature of the mixture is 830 F. and the instantaneous rise of temperature of the economizer oil will be 130 F. and which it will attain in a fraction of a second, whereas if it were heated in a coil to a corresponding degree, it would require several minutes to attain such increase. In other words, the heating time element is probably two to three hundred times as fast by direct admixture as by extraneous heating, and it is this rapid heating of almost explosive violence that produces the breakdown of the molecular structureand causes cracking. I cannot otherwise account for the results obtained by this method as against slower heating, as the yield of gasoline may equal or even exceed the amount obtained in the prlmary cracking operation wherein the temperature may be 75 to 100 F. higher, the same oil being used in both circuits.

Another object of my invention is the improved operating condition which is brought about by the introduction of the secondary supply of oil into the primary supply. It seems to have a marked influence on the character of the carbon formation by creating a condition whereby the carbon is precipitated in a more finely divided state and which is less coherent and is more easily cleaned out of the chamber, andby this improved condition thus created I am enabled to operate for a much longer time without shutting down for carbon removal; heretofore, the running time was largely dependent upon the accumulation of carbon at the point of exit from the chamber, this accumulation gradually building up a differential pressure between the inlet and outlet pressures to such a point that further operation was impractical and cleaning necessary. By my new arrangement, the practical running time is increased to a very great extent and which I have found to be four to ve times as long and in some cases even more. This, however, is largely dependent upon the character of the oil being used in the secondary coil.

The setting of the main furnace may be such that an auxiliary fire may be used to give additional heat to the economizer coil and, under some circumstances, this may be desirable. In my drawing of the apparatus, I show the auxiliary ring or combustion chamber, but it is to be understood that this ,may be dispensed with and good results obtained thereby. I alsoshow in the drawing a heat exchanger apparatus designed to extract heat from the outgoing cracked or converted oil and exchange it to the ingoing oil to be cracked. This may be dispensed with but it is a heat economizer and I show it as a part of the apparatus but it is not an essential part thereof.

I also show a preheater coil situated in the.

hottest portion of the furnace to act as a protector and absorber of radiant heat and excessive heat that Vwould otherwise impinge upon the final or terminal heating coils. This coil and its function is described in my copending -application Serial No. 712,156 filed May 9, 1924.

I am also showing fractionating towers wherein the vapors are fractionated and separated into their various products.

I am showing all this apparatus so that anyone familiar with the art to which this invention relates may be enabled to construct and operate the complete plant.

As before mentioned, I may use an auxiliary lire or supply of heat to obtain closer regulation of the heating in the economizer coil and also to increase the quantity that may be heated; Y this also enables me to secure a somewhat higher heat in the oil or hydrocarbons passing through the economizer coil and thereby increase the final cracking effect.

A heat interchanger may also be employed to preheat the ingoing oil to the economizer coil and extract heat from the outgoing oil, thereby increasing the heating effect in the economizer coil.

The carbon precipitating or mixing chamber will act to catch any free carbon which can be periodically removed by blowing down as described in my Patent No. 1,456,419, or

it may be removed by disengaging the end clean-out closures and removing the carbon or carbonaceous material by hand or otherw1se.

By ,the above described method of operation, the mixing chamber becomes a heating element by the fact that the ingoing oil is of higher temperature from the main cracking coil than that entering from the economizer coil and heat is imparted to the latter.

In my Patent No. 1,426,813, I describe a reaction chamber or digester wherein the cracking reaction is continued outside of the heating coils and itis to be understood that the application of the economizer coil to that type of apparatus is feasible and practical lthe heavy separated in the fractionating apparatus.

. charging it into the carbon I The mixing chamber and its connections der pressure maintained in that portion of the apparatus and will act as a cushion or shock absorber on the pumping system and will have a tendency to smooth the action of the pump and relieve any undue hydrostatic pressure on the tubes, gauges, valves, and other parts of the apparatus.

In the heating and cracking furnace, as depicted in the accompanying drawing, the primary cracking operation is accomplished in the coils substantially as described in my Patent No. 1,456,419. In this case, the injection oil from the economizer coil is introduced into the mixing chamber at a coincident' point with the main portion of cracked oil entering from the primary cracking coils.

The apparatus is so arranged in regard to tanks, pumps, lines, coolers, condensers, etc.,

that the oil or hydrocarbons circulated through the economizer coil can be either a virgin makeup oil or it may be derived from or high-boiling point fractions There is also arrangementmade for bypassing the economizer oil from entering the' carbon precipitatingor mixing chamber and passing it directly to the vaporizing and fractionating tower. This may be desirable at times, either for control or forintroducing stocks into the cracking system. I have found that when a heavy fuel oil or crude oil or in fact any oil which on normal distillation (that is not destructive distillation) will produce viscous residues or fractions, if introduced into the cracking system through the economizer coils and heated to a degree approximating its cracking point, then disprecipitating or mixing chamber or into a digester or reaction chamber, that the heavy viscous fractions contained therein are cracked and rendered 'comparatively non -viscous so that the residues or heavy fractions obtained by 'this method of operating are easilyl pumped or otherwise disposed of.

In this system I' prefer to use a separate l pump for each oil circuit-one for the economizer circuit and one for the main cracking circuit, for several reasons: Flrst, different stocks may be used in the two circuits, and,

second, better control may be obtained. It is quite practical, however, to use one large pumpto feed all the economizer coils and have separate pumps for each main cracking unit where several such units-are in a battery; likewise, a large pum may be employed to feedl all' the main crac 'ng coils but I prefer separate pumps on each p for clearness and 35 ;.lines 34 and'35 y tively. cracking unit. This,

however, here mentioned to wish to construct this invention.

Referring to the drawing:

Figure 1 represents the complete apparatus in part section and part elevation; and

Figure 2 represents the cracking furnace in section at right angles to that shown in Figure 1. Y

Figure 2fshows themixing chamber in its correct position, whereas in Figure 1 it is shown below the furnace and is so depicted simplicity; the balance of the apparatus is so disposed in the drawing as to show the relation of one part to another and is not meant to show the actual position of the various parts.- Similar numbers in Figure 1' and Figure 2 represent like parts.

In the drawing 1 represents the furnace; 2 the preheater coil; 3 the pipe connection from guide anyone who may an apparatus embodying 4; and 5 the connection from the intermediate pipe connection from the inal coils to the carbon precipitating or mixing chamber 8; 9 is a blowdown connection; 10 is a discharge connection from the carbon precipitating or mixing chamber to the heat exchanger 11; 12 is a connection from the heat exchanger to a bypass trap 13; 14 is a connection and 14 is a pressure reducing valve therein connect-c` ing the bypass trap 13 with the discharge header 15, which in turn is connected into the fractionating tower 16, which is divided in various sections 17, 18 and 19; 20 is a-vapor pipe connecting the tower 16 into the fractionating tower 21; 22 and 23 are boiling decks for fractionating the vapors and condensates; 24 is an analyzer or reiuxing conis immaterial to the process,I but is s -the prehcater coil to the intermediate coil'A header not numbered. Tower 21 is fitted with a draw-oil' arrangement 29 connecting with a cooler which in turn con cts to the supply tank and heavy naphtha ank throughlook box 30 and lines 31 and 32.

Compartment 17 is connected by pipe 33 and valve 33 tothe residue tank; compartments 18 and 19 are fitted with draw-off pipes 34 and 35 respectively and are fitted with valves 34 and 35 and a crossover connection and valve 36 between the lines 34 and are connected to the cooler; from the cooler are look-boxes and connections 37 and 38 connecting to the supply tank y and the intermediate naphtha tank respec- The tower compartments are fitted with spray devices 39 and 40, connected by pipe`connections 41 and 42, controlled respec- 1 tively by valve 41 and 42', and thence by pipe 43 to the pump 44. There is a connection 45 and valve 45 leading from pipe 43 and connecting with the analyzer 24. There is also a connection 46 from the analyzer controlled by valve 46 and connecting with the pipe 35 leading to the cooler. There are con` nections 47 and 48 connecting with pipes 35 and 46, respectively, which connect with the fractionating tower 21.. The bypass trap 13 is inserted in water or water jacket 49 and is fitted with a blow-off connection 50; from a point above the bottom a connection 51 is made to the cooler 52 and through line 53 it connects to the control board 54 on which are mounted the c ontrol valves and pressure gauges. On the control board the line 53 is fitted with a terminal pressure gauge 55 and a pressure reducing valve 55, from whence it connects to two tanks, one for slop oil and one for cracked oil, through the line 56 which is fitted with branch lines and valves connect ing with each tank. The pump 44 takes suction through line 57 to the intermediate naphtha tank and also the heavy naphtha tank throu h branch connections, and valves to each ta Pump 58 takes suction through line 59 with the water tank, the slop tank and the supply tank through branch pipes and valves to each tank; pump 58 discharges through line 60 to the control board 54 whereon are mounted a pressure control valve 61 and a pressure gauge 62 in line 60 which extends to and is connected into the preheater coil 2; between lines 56 and 60 is a bypass valve and connection 63. The pump 64 has a suction connection through line 65 and valve 65 to the fresh oil supply tank 84; it also has a branch suction line 66 and valve 66 connecting to the supply tank 83; pump 64 has a discharge pipe 67 connecting with the control board 54 whereon are mounted a pressure control valve 68 and a pressure gauge 69; between lines 67 and 60 on the control board is a bypass valve and connection 70; from .the control board the line 67 extends to the branch connection 71 from the latter extends a line 72 and valve 72 connecting to the heat exchanger 11; the heat exchanger has a corresponding outlet pipe 73 connecting to thejpipe 74; from the branch connection 71 extends a line 74 and valve 74 to the inlet side of the economizer coil 75 in furnace 1; the outlet side of coil 75 connects with the pyrometer fitting 76 which acts as a branch fitting; one branch 77 and valve 77 connects with the mixing chamber 8 and the other branch 78 with its valve 78 connects to the header 15. The furnacel is fitted with a burner 79 and alsoan auxiliary burner 80, also a smoke stack 81; the coilsV 6 are fitted with pyrometer ttings 82 and 82'; 83 is the oil supply tank and 84 is the makup oil or fresh supply tank.

There are a number of instances where l show on the drawingfitting, valves, etc., which I have not numbered, as they are selfevident in. -character ,and anyone familiar with the art to which this invention relates will readily understand their significance and function.

Having 'now described ymy apparatus, I will describe its operation:

The pump 58 is started and takes suction on the supply tank. 83, through line 59 and discharges the oil through line 60 to the control board 54 and through the pressure regulating valve 61 in line 60, from whence'the oil passes to the preheating coil 2, then to the coil 4 by way of pipe 3, then into the "nal heating and cracking coil 6 by way of pipe 5 from the cracking coils 6 the oil passes to the carbon precipitating and mixing chamber 8 by way of pipe 7. At a point in the mixing chamber near the pipe 7 is an entering pipe 77 connected tothe economizer coil 75 which is located in the terminal passes of the furnace l; this coil may have a supply of additional heat furnished by the burner 80, if so desired, in order to increase its capacity and cracking effect. The coil 75 may be supplied with oil through the pipe 74 which connects with the valve 68 on the control board 54; in the line 74 is a bypass 72 connecting with the heat exchanger 11 designed to supply heat to the oil going to the economizer coil and extracting heat from the out-going oil from the carbon precipitating and mixing chamber 8; from the valve 68 on the control.

board extends a pipe 67 connected to the pump 64 which is taking suction on the sup; ply tank and will be pumping for the time being the same oil as is being pumped by the pump 58. y

The oil in the two Adistinct circuits is heated by the heat supplied by the burner 79 and, if desired, the burner may also supply additional heat., The oil in the primary cracking coils 2, also coils 4 and 6, will be heated to an active,cracking-temperature, the quantity of oil pumped and the supply of heat being so regulated as to bring about this result. Now the oil passing through the secondary or economizer coil is so regulated, as to quantity, as to bring its. temperature to a point approximating its cracking point more or less (as previously stated, the quantity pumped may be increased'by employing additional heat from the burner 80, care being taken to so regulate the heat as to maintain a substantial heat differential between the two oils as they leave the heating coils) the two streams of oil are now introduced into the mixing chamber 8 where the oil of lower temperature is instantaneously increased in temperature from an incipient cracking temperature to one of active cracking, thev cracking action being highly accelerated by the rapidity of the increase of heat. This reaction and the two heating steps are carried on under a high pressure suiiicient to prevent material vaporization, the admixture of the two being in a liquid condition. The mixture of oils then passes through the carbon precipitating chamber or mixing chamber (where any free carbon is precipitated) into the heat exchanger 11, thence to the bypass trap 13 which is in open communication through the line 51, cooler 52 and line 53 to the terminal pressure reducing valve 55', the pressure being observed by the gauge 55;

' from the valve 55' extends a line 56 to the slop tank or the cracked oil tan From the bypass trap 13 there is connected an outlet pipe 14 and pressure reducing valve 14 located therein andwhich connects into the header 15, which in turn connects into,

the fractionating tower 16. The header 15 is simply a manifold to receive similar connections toV` 14 from other units in a battery of cracking units and where one tower will Y take care `of the vapors of a battery of units.

In operating in this manner, I prefer to.

use a terminal pressure of one thousand pounds, more or less, with. an inlet pressure suiiciently higher to overcome the friction of the pipe, bends, etc., and which may be as high as one thousand ive hundred pounds, or more. I

The pump 64 may take suction on the fresh supply tank 84, through pipe 65 and valve 65', if it is desired to replenish the system with fresh oil, or the fresh oil may be introduced into the system by putting it into tank 83 and which may be done if the makeup oil is a distillate or is a clean oil that would not cause fouling of the primary coils; whereas. if the make-up oil is a heavy grade, such as fuel or crude oil which might cause fouling of the tubes of the primary coils, then the make-up oil should be stored in tank 84,

so that pump 64 may introduce it into the system through the economizer coil where danger of carbonizing or fouling is a minimum. If, for in stance` fuel or crude oil were introduced into the system by putting it into the supply tank 83. then the pump 58 would dis'- charge the heavy oil through the 'primary cracking coils which would rapidly foul and cause more or less trouble, whereas if the pump 64 handles the make-up or fresh supply oil it can be so regulated that the heating eifect in the economizer coil will be such that nothing more than incipient -cracking will take place therein` the active cracking taking place in the mixing chamber or carbon precipitating chamber, where carbon can be readily cleaned out or purged. By

this arrangement, the coils will remain clean and practically free of carbon.

' The economizer coil also has a bypass connection 78 in which lis a pressure reducing valve 78'; this line is connected to the header 15 and is used as a bypass in case of trouble stock in the fractionatmg towers without" cracking it in the mixing chamber.

The pump 58 maybe operated to furnish the ordinary or economizer coil with its supply of oil and at the same time furnish the primary coils with their supply of oil-(by operating in this way both coils will be supplied with the same grade of oil). The two coils will function in an identical manner as if each had an individual pump, the regulation of the supply to each coil being controlled by suitably situated valves. stance, pump 58 can take suction on the supply tank 83 and discharge through line 60 to the control board 54 and by having'valve 61 open, the primary coils 2, 4 and 6 may be supplied and also valve may be open -through whichthe secondary or economizer coils may be supplied with oil.

The same arrangement applies to pump 64 which may take suction on the supply tank 83 and also on the fresh supply tank 84 and discharge through line 67 to the control board 54 and with valve 68 open, together with valve 7 2' or 74', the secondary or economizer coils will be supplied with oil, and, if valve 70 is simultaneously opened, the primary coils will be supplied with oil--the quantities to each coil being controlled by valve 70 for the primary coils and valve 72' or 7 4' for the secondary coils.

When I wish to blow shut oii'l the supply of oil to pump 58 and open the suction into the water tank, the pump then discharging water to the coils and driving the oil ahead of it; the valve I4 being closed, the oil and water discharges through the bypass trap 13, through pipe 51, cooler 52, pipe 53. pressure reducing valve 55' and line 56 to the slop tank, or if the oil is coming clean it is run into the cracked oil tank. When the oil is displaced' in the tubes, then the blow-off connection 9 on the chamber 8 is opened and the carbon or carbonaceous material is blown out of the tubes and carbon precipitating chamber.

To simultaneously blow down the economizer coil with the primary coils, I close For in-- down the system, I

valve 68 on the control board and open valve 1 encountered in the mixing chamber-this Pressure will be a thousand pounds more or less. .When operating to discharge 1nto the header 15, comparatively low pressure can be employed. When the oil and vapor discharge from the header 15, they enterthe .59 jecting one supply of hydrocarbon oil totower 16, wherein they are fractionated;

"from tower 16 the vapors pass to tower 21 47, having valves 35 where they are further fractionated. Tower 16 willl separate in compartment 17 a heavy residue which is cooled and run to the residue tank.4 Tower 16 will also separate in compartment 18 a cycling stock which may be withdrawn through pipe 34 and valve 34 to the cooler and pipe 37 to the supply tank 83 to be rerun. Tower 16 will also separate in compartment 19 an intermediate naphtha stock which may be withdrawn through pipe 35, valve 35', through the cooler and pipe 38, to the intermediate naphtha tank. The intermediate naphtha may be sprayed into the compartment 18 through spray pipe 39 by opening valve 36 and closing valves 35 and 47, or it may be run to the lower part of the tower 21 through valve and 36 closed.

The residue from tower 21 is a heavy naphtha and may be drawn of through connection 29, thence to the cooler, look box 30, pipe 32, to the heavy naphtha tank, or it may be run to the supply tank 83 through line 31.

The pump 44 is arranged to take suction on the intermediate naphtha and also on the heavy naphtha tanks, so that these stocks may be sprayed into the various tower compartments as a scrubbing and condensing medium and to be revaporized and again fractionated or they may be used as a condensing medium inthe analyzer 24, the oil entering through pipe 45 and valve 45 and dischar ing through pipe 46 and valve 46 througi the cooler, then back to the original tank `from which it came; or by closing valve 46 and opening 48-the oil may be discharged into the lower portion oftower 21 to be refractionated.

The inal vapors leaving tower 21, through the analyzer 24 can be made a light naphtha containing a large percentage of gasoline, or it can be made a crude test gasoline not re uiring further distillation to reneit.

claim:

1. A method of converting hydrocarbon oil of high boiling point into hydrocarbons having lower boiling point comprising subcracking conditions of temperature and pressure, subjecting a second supply of hydrocarbon oil to heat from the same source as used for the first supply',` introducing the second supply to the rst supply after their respective beatings', cooling the resulting Y -mixture to a degree suicient to prevent substantial vaporization when stored under atmospheric pressure conditions, and passing the cooled mixed hydrocarbons to storage.

2.- A, method of converting high boiling point hydrocarbon oil to lower boiling point hydrocarbons comprising heating a primary supply of hydrocarbon 011 in a heating zone `to a degree suiicient to crack them, discharging the heated oil into a reaction zone, maintaining on the primary supply in the heating and reaction zones a pressure suicient to prevent material vaporization of the oil, simultaneously heating a second supply of hydrocarbon oil by hot gases from the heating zone of the rst supply, maintaining thereon suficient pressure to prevent material vaporization thereof, introducing the said secondary supply to the primary supply in the reaction zone, cooling the mixture to a degree suticient to prevent a reaction thereof, and passing the cooled hydrocarbons to storage without substantial vaporization.

3. The process of crackin hydrocarbon oil in substantially the liquld phase comprising heating a primary supply of hydrocarbon oil in a heating furnace to a degree sutiicient to crack them, discharging them into a carbon precipitating and reaction chamber, maintaining throughout the cracking system a pressure suiicient to prevent material vaporization of the oil, and simultaneously heating a secondary supply of hydrocarbon oil in the terminal combustion spaces of the primary heating furnace, maintaining thereon sucient pressure to prevent material vaporization thereof, mixing the secondary and primarysupplies in the reaction chamber, withdrawing the mixture from the reaction chamber and cooling it to a depressure suicient to prevent material vaporization of the oil, simultaneously heating a secondary supply of hydrocarbon oil in a tui bular heating element positioned in the terminal combustion spaces of the primary heating furnace, maintaining thereon a pressure sufficient to prevent material vaporization thereof, introducing said Dsecondary supply to the primary supply in the reaction chamber, cooling the mixture under pressure to a degree suiiicient' to permit storage thereof under substantially atmospheric pressure, and then passing the cooled hydrocarbons to storage.

5. The process of cracking hydrocarbon oil .in substantially the liquid phase comprising heating to cracking temperature a primary supply of hydrocarbon oil in a tubular heating element positioned in a heating furnace, discharging them into `a carbon precipitating and reaction chamber, maintaining on the primary supplyA in the heating and reaction zones a pressure sucient to prevent 1,sso,717

material vaporization of the oil, simultaneously heating in a tubular heating element in the terminal combustion spaces of the primary heating furnace a secondary supply of oil, maintaining thereon sutlicient pressure to prevent material vaporization thereof, introducing said secondary supply to the primary supply in the reaction chamber, passing the mixed hydrocarbons to a cooler wherein they are cooled to a degree sutiicient to permit their storage under substantially atmospheric pressure, and thence passing the cooled mixture to storage.

6. The process of cracking hydrocarbon oil in substantially the liquid phase comprising heating a primary supply of hydrocarbon oil in a heating furnace to a degree sufficient to crack them, discharging them into a carbon precipitating and reaction chamber, maintaining in said heating furnace and carbon precipitating and reaction chamber a pressure sufficient to prevent material vaporization of the oil, simultaneously passing a secondary supply of hydrocarbon oil through a tubular heating element in the terminal com- A bustion spaces of the primary heating furnace, maintaining on said secondary supply a sufficient pressure to prevent material vaporization thereof, introducing said secondary supply to the primary supply in the mixing chamber, passing the resulting mixture in a heat exchange relationship vwith the unheated secondary supply, then further cooling the mixture to a degree sucient to permit its storage under substantially atmospheric pressure, reducing the pressure on the cooled mixture and then passing the hydrocarbons to storage.

In testimony whereof I ailix m signature.

JOHN C. LACK. 

